RT Journal Article SR Electronic T1 Alpha-1-antitrypsin deficiency and increased lung cancer risk JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 950 OP 950 VO 63 IS 11 A1 S K Chhetri YR 2008 UL http://thorax.bmj.com/content/63/11/950.abstract AB